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Difference between revisions of "cpp/container/priority queue/priority queue"

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Constructs new underlying container of the container adaptor from a variety of data sources.
 
Constructs new underlying container of the container adaptor from a variety of data sources.
  
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@1@ Copy-constructs the underlying container {{tt|c}} with the contents of {{tt|cont}}. Copy-constructs the comparison functor {{tt|comp}} with the contents of {{tt|compare}}. Calls {{c|std::make_heap(c.begin(), c.end(), comp)}}.}} This is also the default constructor {{mark until c++11}}
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@1@ Copy-constructs the underlying container {{tt|c}} with the contents of {{tt|cont}}. Copy-constructs the comparison functor {{tt|comp}} with the contents of {{tt|compare}}. Calls {{c|std::make_heap(c.begin(), c.end(), comp)}}.}} {{rev inl|until=c++11| This is also the default constructor.}}
  
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@2@ Move-constructs the underlying container {{tt|c}} with {{c|std::move(cont)}}. Move-constructs the comparison functor {{tt|comp}} with {{c|std::move(compare)}}. Calls {{c|std::make_heap(c.begin(), c.end(), comp)}}. This is also the default constructor {{mark since c++11}}
+
@2@ Move-constructs the underlying container {{tt|c}} with {{c|std::move(cont)}}. Move-constructs the comparison functor {{tt|comp}} with {{c|std::move(compare)}}. Calls {{c|std::make_heap(c.begin(), c.end(), comp)}}. {{rev inl|since=c++11 | This is also the default constructor.}}
  
 
@3@ Copy constructor. The adaptor is copy-constructed with the contents of {{c|other.c}}. The comparison functor is constructed with {{c|std::move(other.comp)}}. {{mark implicit}}
 
@3@ Copy constructor. The adaptor is copy-constructed with the contents of {{c|other.c}}. The comparison functor is constructed with {{c|std::move(other.comp)}}. {{mark implicit}}

Revision as of 17:49, 21 June 2013

 
C++
 
Containers library
 
std::priority_queue
 
(1)
explicit priority_queue( const Compare& compare = Compare(),
                         const Container& cont = Container() );
 (until C++11)
priority_queue( const Compare& compare, const Container& cont );
 (since C++11)
explicit priority_queue( const Compare& compare = Compare(),
                         Container&& cont = Container() );
 (2) (since C++11)
priority_queue( const priority_queue& other );
 (3)
priority_queue( priority_queue&& other );
 (4) (since C++11)
template< class Alloc >
explicit priority_queue( const Alloc& alloc );
 (5) (since C++11)
template< class Alloc >
priority_queue( const Compare& compare, const Alloc& alloc );
 (6) (since C++11)
template< class Alloc >

priority_queue( const Compare& compare, const Container& cont,

                const Alloc& alloc );
 (7) (since C++11)
template< class Alloc >

priority_queue( const Compare& compare, Container&& cont,

                const Alloc& alloc );
 (8) (since C++11)
template< class Alloc >
priority_queue( const priority_queue& other, const Alloc& alloc );
 (9) (since C++11)
template< class Alloc >
priority_queue( priority_queue&& other, const Alloc& alloc );
 (10) (since C++11)
template< class InputIt >

priority_queue( InputIt first, InputIt last,

                const Compare& compare, const Container& cont );
 (11) (since C++11)
template< class InputIt >

priority_queue( InputIt first, InputIt last,
                const Compare& compare = Compare(),

                Container&& cont = Container() );
 (12) (since C++11)

Constructs new underlying container of the container adaptor from a variety of data sources.

1) Copy-constructs the underlying container c with the contents of cont. Copy-constructs the comparison functor comp with the contents of compare. Calls std::make_heap(c.begin(), c.end(), comp).}} This is also the default constructor.(until C++11)
2) Move-constructs the underlying container c with std::move(cont). Move-constructs the comparison functor comp with std::move(compare). Calls std::make_heap(c.begin(), c.end(), comp). This is also the default constructor.(since C++11)
3) Copy constructor. The adaptor is copy-constructed with the contents of other.c. The comparison functor is constructed with std::move(other.comp). (implicitly declared)
4) Move constructor. The adaptor is constructed with std::move(other.c).The comparison functor is constructed with std::move(other.comp). (implicitly declared)
5-10) The following constructors are only defined if std::uses_allocator<container_type, Alloc>::value == true, that is, if the underlying container is an allocator-aware container (true for all standard library containers).
5) Constructs the underlying container using alloc as allocator. Effectively calls c(alloc). comp is value-initialized.
6) Constructs the underlying container using alloc as allocator. Effectively calls c(alloc). Copy-constructs comp from compare.
7) Constructs the underlying container with the contents of cont and using alloc as allocator. Effectively calls c(cont, alloc). Copy-constructs comp from compare.
8) Constructs the underlying container with the contents of cont using move semantics while utilising alloc as allocator. Effectively calls c(std::move(cont), alloc). Copy-constructs comp from compare.
9) Constructs the adaptor with the contents of other.c and using alloc as allocator. Effectively calls c(athor.c, alloc). Copy-constructs comp from other.comp.
10) Constructs the adaptor with the contents of other using move semantics while utilising alloc as allocator. Effectively calls c(std::move(other.c), alloc). Move-constructs comp from other.comp.
11) Copy-constructs c from cont and comp from compare. Then calls c.insert(c.end(), first, last);, and then calls std::make_heap(c.begin(), c.end(), comp);.
12) Move-constructs c from std::move(cont) and comp from std::move(compare). Then calls c.insert(c.end(), first, last);, and then calls std::make_heap(c.begin(), c.end(), comp);.

Contents

Parameters

alloc - allocator to use for all memory allocations of the underlying container
other - another container adaptor to be used as source to initialize the underlying container
cont - container to be used as source to initialize the underlying container
compare - the comparison function object to initialize the underlying comparison functor
first, last - range of elements to initialize with
Type requirements

Template:par req concept Template:par req concept Template:par req concept

Complexity

1,3) O(N log(N) comparisons, where N is cont.size().
Additionally, O(N) calls to the constructor of value_type, where N is cont.size().
2) O(N log(N) comparisons, where N is cont.size().
4-6) Constant.
7) O(N log(N) comparisons, where N is cont.size().
Additionally, O(N) calls to the constructor of value_type, where N is cont.size().
8) O(N log(N) comparisons, where N is cont.size().
9) Linear in size of other.
10) Constant.
11) O(N log(N) comparisons, where N is cont.size() + std::distance(first, last).
Additionally, O(N) calls to the constructor of value_type, where N is cont.size().
12) O(N log(N) comparisons, where N is cont.size() + std::distance(first, last).

Example

Run this code
#include <queue>
#include <vector>
#include <iostream>
#include <functional>
 
int main()
{
    std::priority_queue<int> c1;
    c1.push(5);
    std::cout << c1.size() << '\n';
 
    std::priority_queue<int> c2(c1);
    std::cout << c2.size() << '\n';
 
    std::vector<int> vec={3, 1, 4, 1, 5};
    std::priority_queue<int> c3(std::less<int>(), vec);
    std::cout << c3.size() << '\n';
}

Output: 

1
1
5

See also

 assigns values to the container adaptor
(public member function) [edit]
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